Let-off mechanism for looms



Dec. 2, 1930. c. H.' DRAPER LET-.OFF MECHANISM FOR LOOMS Filed July 16. 1929 2 Sheets-Sheet l ATTORNEY Dec. 2, 1930. c. H. DRAPER LET-OFF MECHANISM FOR Looms 2 She'ets-Sheet 2 Filed July 16, 1929 HIHHHMH y? oLnR H. nassen, on HoPEnALmMAssAcHUsETTs, nssIGNoR To nrtnrnn conromx-I Tron, vor;nominaLa, MASSACHUSETTS; Av CORPORATION-jor MAINE Y.

'Appiicatiii mea my ie, irate.` seriainb. 378,6e5." l

This invention yrelates tollet-oi mechanisms V-or looms :and vmore particularly 'such mecha- 'Y yWoven. As the Weaving proceeds,` the diamfV nisms of the. positive let- OE A type.'v

, v VDuring.Weavingoperations thewarp subl y jected toma longitudinalst'ress rvtension the takeup mechanismfvvhich acts ,progres such tension is subjected to Va 'normal variationbythe shed formation andbeatup which has `beenutilized heretofore to Aenfect positive rotative movement "fof .the Warpfbeam to let ofi the Warp asreqiiired by the fabric being eter of `Warp :ony ,thefbeamf gradually diminishes and Vit has been proposed hereto- `fore to compensate for ythis byimparting in-l `creased.rotative vmovement tothe `be'ain as the diameter of thewarp"decreaseagthus letting o the Warp from full to "empty beam in response tothe 'requirementsof the particu-1 "lar fabriobeingfvvoven.' K- .5

and may vbe reiectedl in "they inished'lcloth,V

Such let-off mechanismshave been practically sucoessfnlforjvveaving certain kindsof fabrics7 but the control'othe let-off from the physical' diameter vof thewarpon the beam is `liabl`e `atftimes to letfoff tollnnch, and at other y times too little,'vvith theresult that thetenA sion on the Warp Will varyfrom time totime T3* especially Where it is of' the `finer gradesy` Instances of the above general chara'cterof positive let-oit mechanisms are'shovvn' andplescribed in the patents to'Drap'erlo Ropei","No.

' .647,815, `dated-Apri17, 19.00;V Roper," No.

744,941, dated Nowar, 'ieoeg mi Roper, No.

' 843,181', dated Feb. 5,1907, `wherein the nor- V mallet-o'ff is controlled froinf the rvhip .roll

through a train of `speed reductionigearing, and compensation for the 'decrease'in the diameter of the vvarp on the beam etfectedby a radius arm connecting the tvvomembers of a compound lever mechanism and movable rela tive thereto by a follower bearing upon the Warp on the beam; I

Inlet-oli mechanisms of Athe l*abovefge'neral type the Warp passes from the Warpl beam over a' yielding Whip Vroll normallynnder. the iniiuence of' spring 'means or its equivalent,

and is consequently movable'fr'om `itsnormall Weaving` position by'variations' in Warp ten- .tension throughout the son Tile Slight moy'amantY of the whipru `due to shed'formation and the beat-iup, Which 1 Will maintain. substantially the sameposition,

'variableonly as stated,` andthevvarp tension fmayfbe termed` its fnormal movement Vhas been utilized to let-oil;lr-` the Warp'` asv refq'uired bythe fabrio` being Woven7 and Awith a y beam `of unvarying diameter the YWhip roll sively to take upthe cloth as-it Vis Woven, and

`Will lremain substantially'the same.'f`As.the

Warp onV the beam gradually diminishes in diameter,` however, the 'wr/hipl roll tvill be: displaced ,a further amount Vand cause increased 1 insure substantiallyl the `saineV tension on the -Warp tension during theinormal let-ofi; To i should be maintained inl its normal lweaving i positiomlvar'iable therefrom only bythebeat-V up and shedding operations, throughout the y weaving operation. ,o y

One of the objectsof'the present invention,

therefore, is to provide a positive let-oil, with means for maintaining the Whip 4roll insub- 'to its normal let-off moye'ments that the Warp may be subjected. to substantially l thej same from full to emptybeam.

The present invention'is a further development oi' thelet-o mechanisms of the patents K mentioned and A,inv addition theretoV provides `meansactuated from a going partof the loom 'ai'id'controlled bythe Whip roll or insuring" a stantially the same Working position subject I l.

Weaving operation substantially uniformwtension'onthe Warp during'vveaving romfull to empty beam.

`The Vinvention and ,novelfeatures thereof Will bestbe made'elearv from the following description and the accompanying 'drawings of one good'formfthereof. A 'in the drawings: y Fig". l is a side elevation'.r4 Witli some parts in section, showing a' loom provided with the pidesei'itinmention;A p n Fig'.l 2 is an enlarged detailvwith parts broken away showing one form ofmeans for moving the'radius connectionbetvveen the membersoi` theV compound paWl carrier ;\V M i Y ,Figx is an enlarged perspective detailvvith parts broken away, showing theoompound pawl carrier vvandradius connection control- V1mg means;

Fig. 4 is a sectional side elevation, showing vthe cam for controlling the position of the radius connection; and

5 is a detail ol" the two-way acting` pawl construction to be described.

rherloom 'trame l maybe of usual construction :in-diras mounted thereon the ecanl:V shaft 2 connected by the pitman 3 to the lay 4, the swords 5 of which are mounted at the lower portion of the loom frame on the lay rocker 6.

The warp beam 7 having` the large pinion S secured thereto and carriedby bearings 9 in the loom trame, the rock shaft l extending transversely ol the loom and having the arms ll. secured thereto, the whip roll l2 mounted inthe arms 1l, the rocker arm 13 secured to the rock shaft l() and normally under the influence of spring` means 14, the connected rod l secured to the rocker arm= 18 and to the pawl setting lever 16' at l?, may all loe of the same general construction as more fully andcompletely shown and described in the patents to which attention has been directed.

Pivotally mounted on the bracket 18` at l!) is the downwardly extending pawl setter 16 havingT the channel-way 20, Fig, 3, and opposed to the pawl setter 16 isthe pawl carrier 2l pivotally mounted at Vits lower end and preferably upon the drive shaft 22, and hav` ing` the channelway or guide 23, and these parts may all be of the same general characteras shown and described in the above mentioned patents.

Mounted upon the pawl carrier 2l is the pawl 24 adapted to engage and actuate'the ratchet 25, which is itself mounted upon the shaft 22, and connected to the gear 26 by a train ot speed reduction gearing 2'? for actuating the warp beam to let oli the warp. These parts need no further description because they are all well shown and described in the prior patents and the details of these features form no part of the present invenlion.

onnectin;- the pawl setter 16 and the pawl carrier 2l is a radius connection 28, the position of which relative to the pawl setter and pawl carrier will determine the amplitude of pawl movement.

As also described in the patents mentioned, the pawl carrier l has a downwardly extending arm 19, thelower end of which is connected at 30 to a rodv'll having a slot 32 in its end portion embracing' a pin 83 on a roeier arm 34 rising from the lay rock shaft 6.

From the construction thus far described and as pointed out in the prior patents, the warp Vwill be subjected to normal variations in tension during weaving due to the shed formation and beat-up, and such variation in tension, which may be regarded as the norm a weaving variation, actuates the pawl setter 1G to set .the pawl back for engagement witl another tooth of the ratchet, andron forward cam 49.

movement of the lay the pawl is actuated to let-off the warp the normal amount required by the fabric being woven.

As the weaving continues, the diameter ol the warp mass on the warp beam gradually decreases and the whip roll will be displaced from its proper weaving position in addition to its normal movement due to shedding and beat-up with a variation in the warp tension, and one of the purposes of the present invention is to provide means responsive to any such displacement ofthe whip roll and consequent varia-tion of warp tension to el'ect return of the whip roll to its normal w ,aving position and restoration of the proper warp. tension. A Mounted upon the loom frame is the bracket 35, one at each side Vot the loom, whicasup- DOrts the rock shalt l0, and the bracket may be adjustable on the loom frame, l s indicated, by the vbolt and slot connection at 8f3. Extending from the bracket 35is an arm 37 carryingr a warp roll 3S over which the warp L passes from the warp beam, as indicated in F 1,. and then over the whip roll l2 and above the rock shaft l() .towards the 'liront orn the loom and the weaving instrumentali ties. A I i Adjustably secured tothe rocker arm l is a bracket 39, and extending downwardly from the bracket 39 but secured rigidly theretois a controller arm 40. The controllerarm "40 may be secured adiustablv to the arm 35),

as indicated at 4l.

The lower end of the controller arm 4() is connected at 42 to a rod 43, which, as will presently appear, controls-the operative condition of a going part of the loom to effect return of the whip rollto its initial or normal Weaving position and change the let-off to accord with the dian'ieter of the warp mass with consequent return of the normal warp tension.

The radius connection 28 is carried by a radius arm 44, Fig. 3, which is pivotally connected at 45 to a lever 46 pivotally mounted at 47 onV a bracket 48 secured to the loom frame, and between its `end portions the lever 46 rests upon, or is controlled by, a

In the present instance of the invention, the lever 46 carries a roll 50 which rests uponthe cam 49.

The cam 49 is mounted upon the shaft 5l, Fig. 2, and secured for rotative movement with the cam are the two ratchets 52 and 53, the teeth of which are oppositely directed, clearly indicated in Fig. 2.

Pivotally mounted for rocking niovement upon the shaft 51 is a pawl carrier 54, the lower end portion of which is connected at 55 Vto a rod 56 which may be conveniently operated from any going part of the loom, and, as shown in the present instance of the invention, the rod 56 is connected at 57 to the rocker arm 34 mounted on the lay rock shaft, the construction being' such thatrduring the movements ofthelay, the pawl cal'- riert will be jrocked upontheishatt 51'.

pavvl carrierV 5{iisn 'pinffon Whichfis mounted the compound pawl," comprising the Vpavvls 59 and L60, the dormer' to `act fupon'frthe teeth ot the"i-at'chetV 52 when thepawl 'isv in operative position, andthe latter to act upon the teeth of the ratchet 53. when itisope'ra'- tively related thereto, 5the result beingrv that when either one of the paw-ls 59 oir- 60l acts upon its associated ratchet it 'will servetoturn the cam i9 and thereby controlv the position of the radius connection; The operative or inoperativer position' vol the -pawls 359 and 60 is dictated by the controller arm ithroufggh a train of as will now "be described. y

Mounted for rockingmovementon thepin `58`1srth`e yoke 6l, Fig, 2, havin gan `elorigated y slot 62 into which projects apin' project- 'Y to letfol and 60, as indicated in Fig. 5;

, Threaded linto 'the endsiof the `screws 64' and 65, the inner ends'fot which are at opposite sides ofthe pin 263, the resul-t being that should the yoke B1 beroclred upon its pivotal lsupport 58,'the compound pawl 59, 60 will be moved'to throw one or the other into action4 or bothinto` a neutral position,

ing from thehub'portion of the two pawls .depending upon theVV amplitude lfof vmovement of thefcontroll-er arm 4:0.

As above stated, thev controller farm-40 connected tofal rod {l3j`which`, as indicated in Fig, 2, is :itseli connected to aA pinfon the lower arm 67 of the [yoke '61. Y Y

From the construction' described it will be apparent lthat should the whiprollv 12be `subjected to usual normal'variations of position 'dueto shed `formation and thebeat-up, the pawl andra-tchet mechanism and Vcombined pawl carrier the ratchet, "but 4should ,the whipY roll be `furtherdisplaced'due, orfinstan'ce, to .the decreasing diameter of thewarp beam, the

i l() will be moved to the right," VFig. l, with the result that the pawl 60 will controller arm be thrown into action and the 'cain'iQ ,thereby rotated 'to permitalower portion of thecaml toA come under the roll Ofotvthejlever thereby lowering,"the` radius' connection and increasing the Vannplitude of .pawl movement whip roll toreturn to normal warptensioning positioinf whereupon, .the 'compound pawl mechanism will assume its central .or 1nactive` positionnand -the warp beam will Vcontinue to be rotated under the lovv'ered'position of the Vradius, connection to* let-oli" the required amount 'of Warp, .due to the'del while the normal tension ofthe warp will continue.

A Should the whip roll displacement be maniinechanism the yoke 6l are' trolled position, portion of `the pawl carrier pin' 68. which `may pass through a. lug 69V i carried by theupper end of the pavvl V.car-V will act to" let-ofi "the reiquired amount,of-warp,V usually'one tooth of additionall warp vand permit the rotating festedby undue slackness of Warp, again the i controlling arm irwill act by its movement to the left, Fig( l, to throw the ripa-wl 59 into action, thereby .rotating the cam vto lift the radius connectionbetvveen the pawl setter and the -pawl `.carrier `and. decrease. ther amount of let-olhandrestorethe whip roll* to proper f'w'ea'ving position'.v` Hereagaim when the amount oilet-o1 has conformed to "the c haracterof fabric being Woven and the VVsize vot' the Warp mass on the beam and the whip roll has assumed itsfnormalposition,

the "compound" pawlgmechanism will assume its neutral p'ositionj `Thus the pre'ent inventionvprovides that duringwthe Weavingjope'ration ,from ull to tension back to normah tain the compo'und-pawlsg andGO in the kposition to'fwhich theyhayebeen' lmoved by the controller arm 40, at least,"s`o1'that they will not too readily depart from their `coni 'and to this end theupper ,54 had a yielding vThejrounded`head of the yieldingv pin is adapted to bear upon one of thethreesurfaces carried by a lug 7l .formed as part of the compoundrpawl 5.9and 60. What isclaimed is:

combination of the warp beain,a yieldingly mounted whip roll, a ratchet and pavvliior rotating the Warp `beam to :let-,oft the warp, apawl 4carrier v and pawl setter fulcrumed `at opposite f. ends',

"a radius vvconnection between thev pavvl carrier 'and setter, means Vbetween the pavvl setter.` and whip roll `forY setting the pawl responsiveto normal variations in whip sov icc

, 105 .1. In alet-oi' mechanism for looms, the

roll'- movement, and means l,connectingthef radius vconnection and' whip roll` forchang -ing the; position ofV the radius connection. responsive to` abnormal .variation in: Whip *roll*v movement.

combination ofthe VWarp beam, a yieldingly mounted,V .whip roll, -a `ratchet and pawl v)for the` warp beam to let off the warp,

av VCompound pawl` .carrier comprising two members Vfulcrumed at their oppositeends,

a relatively ,movable radiusV connection between the two members, means governed vby normal variation in lwarp tension to move one .of saidmembers in setting the pavvl, a controlling device connecting thewhipirollV Vand Ina let-olfY mechanism for flooms, Vthe i tlie radius connection for changing the position oi the radius connection between said members and consequently the amplitude of pawl movement responsive to abnormal variations in whip roll position, and means to move the set pawl to a fixed point.

3. In a let-off4 mechanism for looms, the combination or" the warp beam, a yieldingly mounted whip roll, a ratchet to rotate the warp bca-m to let olf the warp, a pawl carrier pivotally mounted at one end and having a pawl, a pawl setting lever pivoted at its opposite end, a radius connection between Ythe two, connections between the setting lever and whip roll for setting the pavvl under normal variations of warp tension, other connections between the whip roll and radius connection tor moving the latter relative to theV pawl carrier and setting lever in response to abnormal variations in whip roll position from full to empty beam 'for varying the amplitude of pawl carrier movement, and means to move the set pawl to a fixed point to let olf the warp.

et. In a. let-oilE mechanism` for looms, the combination oi the warp beam, ratchet and pawl for rotating the'bea'm to let-oit the warp, a pawl carrier and a pawl setter pivotally mounted at opposite ends,`a. radius connection between the two, and means governed by the tension of the warp for moving the radius connection relatively to the pawl carrier and setter to change the amplitude of pawl carrier movement, and means for operating the pawl carrier.

5. In a let-oi mechanism for looms, the combination of the warp beam, a whip roll, a ratchet operatively connected to the war-p beam, a pawl carrier and pawl setter mounted .tor movement about different centres', a radius connocti on between the two, for rotating` the warp beam to let-oit the warp, means for setting the pawl responsive to normal variations in whip roll movement, and other means for varying the relative positions ot the radius connection and the pawl carrier and setter and consequently the amplitude ot pawl setting movement responsive' to abnormal variations in whip Vroll movement trom full to en'ipty-beam, and means for actuating the pawl to let-oit' the warp.

6. In a let-oil mechanism for looms,the combination ot' the warp beam, a yieldingly mounted whip roll` a ratchet and pawl for rotating the warp beam to let-ott the Warp, a pawl carrier, a pawl setter connected to the whip roll, a shiftable connection between the pawl setter and pawl carrier for setting the pawl in response to normal variations in whip roll movement, and means governed by the Whip roll for varying the position of the shit'table connection between the pawl carrier and pawl setter in response to abnormal variations in whip roll position, and

means for actuating the pawl to let-oit the warp.

7. In a let-off mechanism for looms, the combination of the warp beam, a yieldingly mounted whip roll, a ratchet and pawl for turning the warp beam to let ofi:1 the warp, a compound pawl carrier comprising two levers tulcrumed at opposite ends, a radius connection between the two, cam controlled means for varying the position of the radius connection, and means governed by the position of the whip` roll for causing the cam controlled means to vary the position of the radius connection.

8. In a let-oli" mechanism for looms, the combination oit the warp beam, a yieldingl)v mounted whip roll, a ratchet and pawl for turning the warp beam to let off the warp, a compound pawl carrier comprising two levers fulcrumed at opposite ends, a radius arm carrying a radius projection connecting the members of the pawl carrier, a cam for varying the position vof the radius projection to increase or ydecrease the amplitude of pawl carrier movement, and connections from the whip roll for governing the position of the cam in response to variations in whip roll movement.

9. In a let-ofi3 mechanism for looms, the combination of the warp beam, a ratchet and pawl for turning the warp beam toy let oli' the warp, a compound pawl carrier comprising two levers pivoted at opposite ends, a radius arm carrying a radius projection connecting the two levers, means for setting the pawl in response to normal variation in warp tension, a cam for controlling the radius arm and radius projection, means for operating the cam, a device movable inresponse to` abnormal variations in whip roll position for controlling the cam operating means, and means for operating the pawl.

10. In a positive let-oft' mechanism for looms, the combination of the warp beam, means for positively'rotating the warp beam to let of the warp including two members fulcrumed at opposite ends, means ior actuatingv one `of said members, a radius connection between the two members and movable `relative thereto, and means controlled by variation in warp` tension for moving the radius connection relative to thetwo fulcrumed members to increase or decrease the rotative movement of the warp beam.

1l. In a let-off mechanism for looms, the combination o'l' the warp beam, a yieldingly mounted whip roll, a ratchet and pawl and operating means for the latter for positively turning the warp beam to let-oli' the warp governed by normal movement of the whip roll due toshed formation and beat-up, other means actuated from a going part of the loom for maintaining the whip roll in normal weaving position,`anol devices controlled by any abnormal movement of the whip roll Vfor.determining'the operative or non-operaxtive condition of said othermeans thatthe VWhip roll .shall be returned to its normal position if abnormally displaced and thereby maintain the Warp under substantially p uniform tension.

l2. In a positive let-oil' mechanism for looms, the combination of the Warp beam,

a Whip roll, yielding means actingr to hold the Whip roll in normal Weavingposition With the Warp under predetermined amount v of tension, mechanism governed by normal maintained under the predetermined Weaving` tension, and devices connected to the movements of the Whip roll for positively turning the Warp beam to ,let-off the Warp, means actuated from ay going ypart of the loom for returning` thevvhip roll to normal Weaving position should it have been displaced therefrom soy that the Warp shall be Whip roll for .controlling the operative or operative condition of said means.

13. In al positive let-off mechanism for looms, the combination of the Warp beam,

a yieldingly 'mounted` Whip roll, 'a ratchet toy rotate the Warp beam to let-off the Warp, a pawl carrier carryinga pawl, a pavvl setter, a shiftable connection between the pawl' carrier and setter for setting the paWl under normal variations of Warp tension,v mechanism for shifting` the connection between the pawl carrier and setter to vary the .amount of Warp let-olf from the Warp beam under abnormal tensionof the Warp, and a controller connected to the Whip roll for governing the operation of said mechanism in accordance With the abnormal `tension on the l Warp.

In testimony whereof, I have signed my name to this specification.

CLARE H. DRAPER. 

